package com.said.today.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.said.today.dto.Result;
import com.said.today.entity.VoucherOrder;
import com.said.today.mapper.VoucherOrderMapper;
import com.said.today.service.ISeckillVoucherService;
import com.said.today.service.IVoucherOrderService;
import com.said.today.utils.RedisIdWorker;
import com.said.today.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    // private BlockingQueue<VoucherOrder> orderTask = new ArrayBlockingQueue<>(1024*1024);
    private ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    static{
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    @PostConstruct // 类初始化后执行
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable{
        String queueName = "stream.order";
        @Override
        public void run() {
            while (true){
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 BLOCK 2000 STREAMS streams.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    // 2.判断消息是否获取成功
                    if(list == null || list.isEmpty()){
                        // 2.1如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    // 3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 4.如果获取成功，可以下单
                    handlerVoucherOrder(voucherOrder);
                    // 5.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e){
                    log.error("处理订单异常");
                    handlerPendingList();
                }
            }
        }

        private void handlerPendingList() {
            while (true){
                try {
                    // 1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 BLOCK 2000 STREAMS streams.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    // 2.判断消息是否获取成功
                    if(list == null || list.isEmpty()){
                        // 2.1如果获取失败，说明pending-list中没有异常消息，结束循环
                        break;
                    }
                    // 3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 4.如果获取成功，可以下单
                    handlerVoucherOrder(voucherOrder);
                    // 5.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e){
                    log.error("处理订单异常");
                    try {
                        Thread.sleep(2);
                    } catch (InterruptedException ex) {
                        throw new RuntimeException(ex);
                    }
                }
            }
        }

        /* @Override
        public void run() {
            while (true){
                try {
                    // 获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTask.take();
                    // 创建订单
                    handlerVoucherOrder(voucherOrder);
                } catch (Exception e){
                    log.error("处理订单异常");
                }
            }
        } */
    }

    private void handlerVoucherOrder(VoucherOrder voucherOrder){
        // 获取用户
        Long userId = voucherOrder.getUserId();
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        // 获取锁
        boolean isLock = lock.tryLock();
        // 判断锁是否获取成功
        if(!isLock){
            log.error("不能重复下单！");
            return;
        }
        try {
            // 获取代理对象（事务）
            proxy.createVoucherOrder(voucherOrder);
        }finally{
            // 释放锁
            lock.unlock();
        }
    }

    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户
        Long userId = UserHolder.getUser().getId();
        // 获取订单id
        long orderId = redisIdWorker.nextId("order");
        // 1.执行lua脚本
        Long redult = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId));
        // 2.判断结果是否为0
        int value = redult.intValue();
        if(value != 0){
            // 3.不为0，没有购买资格
            return Result.fail(value==1?"库存不足！":"不能重复下单");
        }
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        // 6.返回订单id
        return Result.ok(orderId);
    }
    /* @Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户
        Long userId = UserHolder.getUser().getId();
        // 1.执行lua脚本
        Long redult = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString());
        // 2.判断结果是否为0
        int value = redult.intValue();
        if(value != 0){
            // 3.不为0，没有购买资格
            return Result.fail(value==1?"库存不足！":"不能重复下单");
        }
        // 4.为0有购买资格，把下单信息阻塞到队列
        long orderId = redisIdWorker.nextId("order");
        // 5.创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        // 5.1订单id
        voucherOrder.setId(orderId);
        // 5.2用户id
        Long userId2 = UserHolder.getUser().getId();
        voucherOrder.setUserId(userId2);
        // 5.3代金券id
        voucherOrder.setVoucherId(voucherId);
        // 5.4放入阻塞对象
        orderTask.add(voucherOrder);
        // 5.5获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        // 6.返回订单id
        return Result.ok(orderId);
    } */
    /* @Override
    public Result seckillVoucher(Long voucherId) {
        // 1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        // 2.判断是否开始秒杀
        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
            // 尚未开始
            return Result.fail("秒杀尚未开始！");
        }
        // 3.判断是否秒杀结束
        if(voucher.getEndTime().isBefore(LocalDateTime.now())){
            // 尚未开始
            return Result.fail("秒杀已经结束！");
        }
        // 4.判断库存是否充足
        if(voucher.getStock() < 1){
            return Result.fail("库存不足！");
        }
        Long userId = UserHolder.getUser().getId();
        // 创建锁对象
        // SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        // 获取锁
        boolean isLock = lock.tryLock();
        // 判断锁是否获取成功
        if(!isLock){
            return Result.fail("不能重复下单！");
        }
        try {
            // 获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return createVoucherOrder(voucherId);
        }finally{
            // 释放锁
            lock.unlock();
        }

    } */

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        // 5.一人一单
        Long userId = voucherOrder.getUserId();
        // 5.1查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder).count();
        // 5.2判断是否存在
        if(count>0){
            log.error("用户已经购买过了！");
        }
        // 6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock -1") // set stock = stock - 1
                .eq("voucher_id", voucherOrder).gt("stock",0) // where id=？
                .update();
        if(!success){
            log.error("库存不足！");
        }
        save(voucherOrder);
    }
}
